June 16, 2016, © Leeham Co.: “I’m working on six or eight engines. The more the better.”
This startling statement comes from Alan Epstein, vice president of technology and the environment for Pratt & Whitney.
It runs counter to everything the airline industry has believed since the introduction of the twin-engine Boeing 767 was qualified for ETOPS in the early 1980s: fewer engines are better.
Epstein explained his statement during an interview with LNC at the United Technologies Media Days last week in Hartford (CT).
Epstein last year at the same event told LNC he was looking at four-engine technology for future airplanes. We asked him this year if he was still looking at four engines. That’s when he said he was looking at six.
It’s his job to think outside the box. This one clearly qualifies.
“In the mid-1990s, the engine people were whining that engines had become a commodity,” Epstein explained. “On the [Boeing] Triple 7, you could buy a Rolls or a Pratt or a GE engine. There wasn’t much to differentiate them except price. It’s a commodity. The airplane seemed to have the same capability. That was an anathema to the engine companies.
“People attacked it different ways,” Epstein said. “GE went and bought exclusives. They did it with money. They put big money up front. UTC decided to do it with technology. The GTF was a differentiator. Technology changed the business.”
Epstein said that in 2007 he discovered there was a paper in 1957 that laid out the case, “Why not use small engines?” rather than one big engine.
“I thought, why not examine their hypotheses and assumptions and see what’s changed in 50 years,” he said.
Epstein said engine accessories in 1957 didn’t scale, but they do today; electronic fuel control systems, for example. Engines also become lighter when they are smaller.
“When I gave a lecture on this, someone came up and said you can’t use a large number of engines. Do you realize how much time it will take just to check the oil?” Epstein said that today cars have an oil indicator and no dip sticks. “If my car can check the oil automatically, my airplane can check it automatically.”
Because engines are commodities, he said smaller, lighter engines in greater numbers on airplanes means an aircraft could be dispatched with one of many engines inoperative. Diversions would also be reduced, although he concedes that the engines today are incredibly reliable.
From an economic point of view, Epstein said, the engine shut down rate in the 1960s was 500 per million flight hours. The V2500s today are less than one in a million.
Smaller engines might invite new entrants into the field. It would also mean a company like PW could build hundreds of thousands of engines a year.
“It would be a disruptive technology to have that kind of propulsion system,” Epstein said. If the incumbent OEMs didn’t do it, some new entrant might, he said.
Read more of our interview with Alan Epstein behind our paywall today.